Releasable and Interchangeable Connections for Golf Club Heads and Shafts

ABSTRACT

Golf club heads are releasably engaged with shafts so that the club heads and shafts can be readily interchanged and/or so that the shaft position with respect to the club head can be readily changed. Assemblies for connecting the club head and shaft may include: (a) a cylindrical structure having a cylindrical interior chamber for receiving a golf club shaft, a rotation-inhibiting structure, and a securing structure; and (b) a securing system for releasably engaging the securing structure. The club head and shaft may be changed by releasing the securing system and exchanging the original parts with different parts. Furthermore, the shaft may be bent or otherwise extend at an angle from the shaft connection assembly so as to allow adjustment of the shaft position with respect to the club head.

FIELD OF THE INVENTION

This invention relates generally to golf clubs and golf club heads. More particularly, aspects of this invention relate to golf clubs having releasable connections between the golf club head and the shaft and/or head/shaft position adjusting features to allow easy interchange of shafts and heads and/or to allow easy modification of the head/shaft positioning properties.

BACKGROUND

Golf is enjoyed by a wide variety of players—players of different genders and dramatically different ages and/or skill levels. Golf is somewhat unique in the sporting world in that such diverse collections of players can play together in golf events, even in direct competition with one another (e.g., using handicapped scoring, different tee boxes, in team formats, etc.), and still enjoy the golf outing or competition. These factors, together with the increased availability of golf programming on television (e.g., golf tournaments, golf news, golf history, and/or other golf programming) and the rise of well known golf superstars, at least in part, have increased golf's popularity in recent years, both in the United States and across the world.

Golfers at all skill levels seek to improve their performance, lower their golf scores, and reach that next performance “level.” Manufacturers of all types of golf equipment have responded to these demands, and in recent years, the industry has witnessed dramatic changes and improvements in golf equipment. For example, a wide range of different golf ball models now are available, with balls designed to complement specific swing speeds and/or other player characteristics or preferences, e.g., with some balls designed to fly farther and/or straighter; some designed to provide higher or flatter trajectories; some designed to provide more spin, control, and/or feel (particularly around the greens); some designed for faster or slower swing speeds; etc. A host of swing and/or teaching aids also are available on the market that promise to help lower one's golf scores.

Being the sole instrument that sets a golf ball in motion during play, golf clubs also have been the subject of much technological research and advancement in recent years. For example, the market has seen dramatic changes and improvements in putter designs, golf club head designs, shafts, and grips in recent years. Additionally, other technological advancements have been made in an effort to better match the various elements and/or characteristics of the golf club and characteristics of a golf ball to a particular user's swing features or characteristics (e.g., club fitting technology, ball launch angle measurement technology, ball spin rates, etc.).

Given the recent advances, there is a vast array of golf club component parts available to the golfer. For example, club heads are produced by a wide variety of manufacturers in a variety of different models. Moreover, the individual club head models may include multiple variations, such as variations in the loft angle, lie angle, offset features, weighting characteristics (e.g., draw biased club heads, fade biased club heads, neutrally weighted club heads, etc.). Additionally, the club heads may be combined with a variety of different shafts, e.g., from different manufacturers; having different stiffnesses, flex points, kick points, or other flexion characteristics, etc.; made from different materials; etc. Between the available variations in shafts and club heads, there are literally hundreds of different club head/shaft combinations available to the golfer.

Club fitters and golf professionals can assist in fitting golfers with a golf club head/shaft combination that suits their swing characteristics and needs. Conventionally, however, golf club heads are permanently mounted to shafts using cements or adhesives. Therefore, to enable a golfer to test a variety of head/shaft combinations, the club fitter or professional must carry a wide selection of permanently mounted golf club head/shaft combinations (which takes up a considerable amount of storage space and inventory costs) or the club fitter or professional must build new clubs for the customer as the fitting process continues (which takes a substantial amount of time and inventory costs). The disadvantages associated with these conventional options serve to limit the choices available to the golfer during a fitting session and/or significantly increase the expense and length of such a session.

SUMMARY

The following presents a general summary of aspects of the invention in order to provide a basic understanding of the invention and various features of it. This summary is not intended to limit the scope of the invention in any way, but it simply provides a general overview and context for the more detailed description that follows.

Aspects of this invention relate to systems and methods for connecting golf club heads to shafts in a releasable manner so that the club heads and shafts can be readily interchanged and/or so that the angle and/or position of the shaft with respect to the club head body (and its ball striking face) can be readily changed. Golf club head/shaft connection assemblies in accordance with examples of this invention may include: (a) a cylindrical structure having a first end and a second end opposite the first end, wherein the first end includes a first opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure includes a rotation-inhibiting structure, and wherein the second end includes a securing structure; and (b) a securing system for releasably engaging the securing structure.

Further aspects of this invention relate to golf clubs in which the shaft is engaged with the golf club head using a shaft/club head connection member of the type described above. Such golf clubs may include: (a) a golf club head having a shaft-receiving chamber, wherein a first end of the shaft-receiving chamber includes a first rotation-inhibiting structure and a second end of shaft-receiving chamber includes a first opening for receiving a securing member; (b) a shaft connection member extending into the shaft-receiving chamber of the golf club head, the shaft connection member including a structure as generally described above; (c) a shaft engaged in the cylindrical interior chamber of the shaft connection member; (d) a securing member received through the second end of the shaft-receiving chamber of the golf club head and releasably engaging the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with the golf club head; and/or (e) a grip member engaged with the free end of the shaft.

The club head and shaft may be interchanged with respect to one another by releasing the securing system and interchanging the originally present parts (e.g., shafts, club heads, etc.) with different parts, e.g., having different characteristics. Furthermore, the shaft may be angled and/or the chamber for receiving the shaft in the shaft connection member may be angled or otherwise offset with respect to the axial direction of the shaft connection member so as to allow adjustment of the angle or position of the shaft with respect to the club head (e.g., with respect to its ball striking face).

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and certain advantages thereof may be acquired by referring to the following detailed description in consideration with the accompanying drawings, in which:

FIG. 1 generally illustrates a front view of an example golf club according to this invention;

FIGS. 2A through 2C illustrate various views of an example golf club head/shaft connection member that may be used in accordance with examples of this invention;

FIGS. 3A through 3E illustrate example features of a connection between a golf club head and a shaft utilizing a golf club head/shaft connection member in accordance with an example of this invention; and

FIGS. 4A through 6B illustrate various example features and structures that allow adjustment of various characteristics of a golf club, such as loft angle, lie angle, etc., utilizing golf club head/shaft connection members in accordance with examples of this invention.

The reader is advised that the attached drawings are not necessarily drawn to scale.

DETAILED DESCRIPTION

In the following description of various example structures in accordance with the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example connection assemblies, golf club heads, and golf club structures in accordance with the invention. Additionally, it is to be understood that other specific arrangements of parts and structures may be utilized, and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top,” “bottom,” “front,” “back,” “rear,” “side,” “underside,” “overhead,” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures and/or the orientations in typical use. Nothing in this specification should be construed as requiring a specific three dimensional or spatial orientation of structures in order to fall within the scope of this invention.

A. General Description of Golf Club Head/Shaft Connection Assemblies and Golf Clubs Including Such Assemblies According to Examples of the Invention

In general, as described above, aspects of this invention relate to systems and methods for connecting golf club heads to shafts in a releasable manner so that the club heads and shafts can be readily interchanged and/or repositioned with respect to one another. More detailed descriptions of aspects of this invention follow.

1. Example Golf Club Head/Shaft Connection Assemblies and Golf Club Structures According to the Invention

One aspect of this invention relates to golf club head/shaft connection assemblies for securely, but releasably, connecting a golf club head and shaft. Such assemblies may include, for example: (a) a cylindrical structure having a first end and an opposite second end, wherein the first end includes a first opening providing access to a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure (e.g., nearer to the first end than the second end) includes a rotation-inhibiting structure, and wherein the second end includes a securing structure; and (b) a securing system for releasably engaging the securing structure. While a variety of different securing structures and securing systems may be used without departing from this invention, in some example structures according to this invention, the securing structure will include a threaded hole defined in the second end of the cylindrical structure, and the securing system will include a threaded bolt element that engages the threaded hole. The cylindrical interior chamber and the threaded hole may be coaxial or non-coaxial, and optionally, they may be provided in the cylindrical structure completely independent from one another.

A variety of rotation-inhibiting structures and systems may be used without departing from this invention. In some example structures according to this invention, the rotation-inhibiting structure may include plural flat sides that extend in an axial direction of the cylindrical structure (optionally to form a polygon cross section having from 3-25 sides). In some more specific examples, the polygon cross section of the cylindrical structure that forms the rotation-inhibiting structure will have at least 4 flat sides (or even at least six or eight flat sides). Other non-round cross sectional configurations may be provided as part of the rotation-inhibiting structure without departing from this invention (e.g., star or asterisk shaped exterior surfaces, oval or elliptical shaped exterior surfaces, non-regular or non-symmetrically shaped exterior surfaces, etc.).

The rotation-inhibiting structure may extend along any desired portion of an overall longitudinal (or axial) length of the cylindrical structure without departing from this invention. In some more specific examples, the rotation-inhibiting structure will extend less than 50% of an overall axial length of the cylindrical structure, or even less than 35% of the overall axial length. On the other hand, the rotation-inhibiting structure, when present on the exterior surface of the cylindrical structure, will extend a sufficient portion of the overall longitudinal or axial length of the cylindrical structure so as to provide a solid, non-rotational engagement and feel (e.g., at least 2% of the overall axial length). In some more specific examples, the rotation-inhibiting structure will extend from 2-65% of the overall axial length of the cylindrical structure, or even from 5-50% or even 10-35% of the overall axial length.

The exterior surface of the cylindrical structure and its cylindrical interior chamber may be coaxial. On the other hand, these cylindrical structures need not be coaxial (e.g., they may extend in different directions, they may extend in parallel but in a non-coaxial direction, etc.). By providing non-coaxial cylindrical interior and exterior surfaces (or through other features of the club head, shaft, etc.), various properties, positions, angles, and the like of the shaft with respect to the club head ball striking face may be changed, as will be explained in more detail below. If desired, the exterior surface of the cylindrical structure (e.g., at the first end thereof) may includes a rotational position indicator to allow a user to easily see the position of the shaft/club head connection member with respect to the club head when in use.

Aspects of this invention further relate to golf clubs in which the shaft is engaged with the golf club head using shaft/club head connection members of the types described above. Such golf clubs may include: (a) a golf club head having a shaft-receiving chamber, wherein a first end of the shaft-receiving chamber includes a first rotation-inhibiting structure and a second end of the shaft-receiving chamber includes a first opening for receiving a securing member; (b) a shaft connection member extending into the shaft-receiving chamber of the golf club head, the shaft connection member including a cylindrical structure having a first end and an opposite second end, wherein the first end of the shaft connection member includes a second opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure includes a second rotation-inhibiting structure that engages the first rotation-inhibiting structure, and wherein the second end includes a securing structure; (c) a shaft engaged in the cylindrical interior chamber of the shaft connection member; (d) a securing member extending into the second end of the shaft-receiving chamber of the golf club head and releasably engaging the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with the golf club head; and/or (e) a grip member engaged with the free end of the shaft. The securing member may be inserted into the shaft-receiving chamber of the club head through an opening provided in the sole of the club head.

The rotation-inhibiting structure of the club head may constitute an opening having side walls or edges of the same non-round construction (e.g., polygonal, flat-sided, non-regular, etc.) as the rotation-inhibiting structure of the shaft/club head connection member as described above. Alternatively, if desired, the club head's opening or side walls may be differently shaped from the rotation-inhibiting structure of the connection member, but it may include appropriately located retaining walls, edges, or other structures so as to securely hold the connection member in a non-rotational manner.

2. Example Methods of Producing Golf Club Head/Shaft Connection Assemblies and Golf Clubs Including Such Assemblies According to the Invention

Another aspect of this invention relates to methods of producing club head/shaft connection assemblies in accordance with examples of this invention (e.g., of the types described above). Such methods may include, for example: (a) producing a shaft connection member as a cylindrical structure having a first end and an opposite second end (e.g., via casting or molding processes, via extrusion, etc.); (b) producing an open cylindrical interior chamber for receiving a golf club shaft at the first end of the shaft connection member (e.g., via drilling or machining processes, etc.); (c) forming a rotation-inhibiting structure as part of an exterior surface of the cylindrical structure, e.g., nearer to the first end than the second end (e.g., by grinding, machining, etc.); (d) forming a securing structure at the second end of the shaft connection member (e.g., by drilling, tapping, or machining processes, etc.); and (e) providing a securing member for engaging the securing structure (e.g., by manufacturing it, from third party suppliers, etc.). If desired, the securing structure may be formed as a threaded hole defined in the second end of the cylindrical structure and the securing member may be provided as a threaded bolt element that is engagable with the threaded hole. The assembly may be formed so as to include any of the various structures and/or configurations described above (and described in more detail below).

Another aspect of this invention relates to methods of assembling golf clubs using club head/shaft connection assemblies in accordance with examples of this invention. Such methods may include: (a) providing a golf club head having a shaft-receiving chamber (e.g., by manufacturing it, from a third party supplier, etc.), wherein a first end of the shaft-receiving chamber includes a first rotation-inhibiting structure and a second end of shaft-receiving chamber includes a first opening for receiving a securing member; (b) engaging a shaft with a shaft connection member, wherein the shaft connection member includes a cylindrical structure, e.g., of the types described above; (c) placing at least a portion of the shaft connection member into the shaft-receiving chamber of the golf club head such that the first rotation-inhibiting structure engages a rotation-inhibiting structure provided with the shaft connection member to thereby inhibit rotation of the shaft connection member with respect to the golf club head; (d) placing a securing member into the second end of the shaft-receiving chamber; and (e) releasably engaging the securing member with a securing structure provided with the shaft connection member to thereby releasably engage the shaft connection member with the golf club head.

If desired, various characteristics or features of the club head may be changed, e.g., by changing a position of the shaft with respect to the club head (e.g., by rotating the shaft and its connection member with respect to the club head when the shaft is bent or when the cylindrical interior shaft receiving chamber of the connection member is non-coaxial with respect to its exterior cylindrical surface) to thereby change the loft, lie, offset, inset, or other features of the club head. Such methods may include: (a) releasing or disengaging the shaft connection member with respect to the golf club head; (b) changing a position of the shaft connection member with respect to the golf club head (e.g., by rotating them with respect to one another) to thereby alter a position of a free end of the shaft with respect to a ball striking face of the club head; and (c) releasably engaging the securing member with the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with respect to the golf club head at the changed position.

Additionally, or alternatively, aspects of the invention allow easy interchange of one shaft for another on the club head (or one club head for another on the shaft). Such methods may include: (a) releasing or disengaging the shaft connection member with respect to the golf club head; (b) engaging a second shaft with a second shaft connection member, wherein the second shaft connection member may include the various structures described above; (c) placing at least a portion of the second shaft connection member into the shaft-receiving chamber of the golf club head such that the first rotation-inhibiting structure of the shaft-receiving chamber engages the rotation-inhibiting structures provided on the second shaft connection member to thereby inhibit rotation of the second shaft connection member with respect to the golf club head; (d) placing the securing member into the second end of the shaft-receiving chamber; and (e) releasably engaging the securing member with a securing structure provided with the second shaft connection member to thereby releasably engage the second shaft connection member with the golf club head. In a similar manner to that described above, a given shaft (and shaft connection member) may be readily disengaged from a club head and engaged with a different club head in accordance with still additional aspects of this invention.

Specific examples of the invention are described in more detail below. The reader should understand that these specific examples are set forth merely to illustrate examples of the invention, and they should not be construed as limiting the invention.

C. Specific Examples of the Invention

FIG. 1 generally illustrates an example golf club 100 in accordance with at least some examples of this invention. This club 100 includes a club head 102, a releasable club head/shaft connection region 104 that connects the club head to a shaft 106 (which will be described in more detail below), and a grip member 108 engaged with the shaft 106. While a driver/wood-type golf club head 102 is illustrated in FIG. 1, aspects of this invention may be applied to any type of club head, including, for example: fairway wood club heads; iron type golf club heads (of any desired loft, e.g., from a 0-iron or 1-iron to a wedge); wood or iron type hybrid golf club heads; putter heads; and the like. The club heads may be made from any desired materials, in any desired construction and/or in any desired manner, including from conventional materials, in conventional constructions, in conventional manners, as are known and used in the art, optionally modified (if necessary, e.g., in size, shape, inclusion of structures, etc.) to accommodate the releasable club head/shaft connection parts.

Any desired materials also may be used for the shaft member 106, including conventional materials that are known and used in the art, such as steel, graphite, polymers, composite materials, combinations of these materials, etc. Optionally, if necessary or desired, the shaft may be modified (e.g., in size, shape, etc.) to accommodate the releasable club head/shaft connection parts. The grip member 108 may be engaged with the shaft 106 in any desired manner, including in conventional manners that are known and used in the art (e.g., via cements or adhesives, via mechanical connections, etc.). Any desired materials may be used for the grip member 108, including conventional materials that are known and used in the art, such as rubber, polymeric materials, cork, rubber or polymeric materials with cord or other fabric elements embedded therein, cloth or fabric, tape, etc. Optionally, if desired, the grip member 108 may be releasably connected to the shaft 106 using a releasable connection like releasable connection 104 (examples of which will be described in more detail below).

The releasable connection 104 between golf club heads and shafts in accordance with examples of this invention now will be described in more detail in conjunction with FIGS. 2A through 3E. FIGS. 2A through 2C illustrate an example club head/shaft connection member 200 in accordance with this invention. As shown, the club head/shaft connection member 200 includes a generally cylindrical body 202 having a first end 204 and an opposite second end 206. The first end 204 defines an opening to an interior cylindrical chamber 208 for receiving the end of a golf club shaft 106. The second end 206 includes a securing structure (e.g., a threaded hole 210 in this example structure) that assists in securely engaging the connection member 200 to a club head body as will be explained in more detail below. In this example structure, as shown in FIG. 2B, the interior chamber 208 is not open to the threaded hole 210, but if desired, the threaded hole 210 may extend to and open in to the interior chamber 208 in some structures in accordance with this invention.

As shown, a least a portion of the first end 204 of the connection assembly 200 includes a rotation-inhibiting structure 212. While a variety of rotation-inhibiting structures may be provided without departing from this invention, in this example structure, the rotation-inhibiting structure 212 constitutes a cylindrical area having a non-round cross section such that when it is fit into a close fitting and similarly shaped opening or chamber, the non-rounded sides and edges of the rotation-inhibiting structure 212 will prevent rotation of the connection assembly 200 with respect to the member into which it is fit (e.g., a golf club head, as will be explained in more detail below). While a variety of non-rounded cross sectional structures may be used without departing from the invention, in the illustrated example, a portion of the first end 204 of the cylindrical body 202 has a polygon shaped cross section having plural (eight) flat sides 212 a.

The rotation-inhibiting structure 212 may extend along any desired portion of the overall longitudinal length L of the connection assembly 200. For example, the length l of the rotation-inhibiting structure 212 may be less than 65% of the overall length L of the connection assembly 200, and in some examples, it may be less than 50%, less than 35%, or even less than 25% of the overall axial length L. On the other hand, rotation-inhibiting structure 212 may extend along any desired portion of the overall longitudinal length L of the connection assembly 200. For example, the rotation-inhibiting structure 212 should be of sufficient length l to enable strong and secure engagement with the club head in a non-rotational manner. As some more specific examples, the length l may be at least 2% of the overall length L of the connection assembly 200, and in some examples at least 5%, at least 10%, or even least 20% of the overall axial length L. If desired, the rotation-inhibiting structure 212 may extend from 2-65% of the overall axial length L of the connection assembly 200, or even from 5-50% or 10-35% of the overall length L.

FIGS. 2A through 2C further illustrate that the first end 204 of the club head/shaft connection member 200 includes an expanded portion 214. As will be more apparent from FIGS. 3A through 3E, this expanded portion 214 provides a stop that prevents the connection member 200 from extending into the club head body and provides a strong base for securing the connection member 200 to the club head body. Also, the exterior shape of the first end 204 may be tapered to provide a smooth transition between the shaft 106 and the club head 102 and a conventional aesthetic appearance.

Other features of this example connection member structure 200 may be seen from FIGS. 2A through 2C. For example, in this example structure 200, the threaded hole 210 of the securing structure (in the second end 206 of the connection member 200) is coaxial with the cylindrical interior chamber 208 (see common axial line 216) and coaxial with respect to the exterior surface 218. These features are not requirements. Rather, if desired, one of these cylindrical holes 208 and 210 may be offset (and still parallel) with respect to the other and/or with respect to the exterior surface 218. As another example, if desired (and as illustrated in FIGS. 6A and 6B), one hole may be angled with respect to the other and/or with respect to the exterior surface 218. As still another example, if desired, multiple threaded holes (or other securing structures) may be included at the second end 206 to enable engagement with multiple bolts (or other securing systems).

The connection member 200 may be made from any desired materials and from any desired number of independent parts without departing from this invention. In this illustrated example, the entire connection member 200 is made as a unitary, one-piece construction from conventional materials, such as metals or metal alloys, plastics, and the like. In at least some example structures according to this invention, the connection member will be made from a titanium, aluminum, magnesium, steel, or other metal or metal alloy material. The various holes (e.g., chamber 208 and threaded opening 210) and/or surface structures (e.g., flat panels 212 a, expanded portions) may be produced in the material in any desired manner without departing from the invention, including via production methods that are commonly known and used in the art, such as by drilling, tapping, machining, lathing, extruding, grinding, etc.

One example of engagement of a golf club shaft 106 with a club head 102 utilizing connection assembly 200 now will be described in more detail in conjunction with FIGS. 3A through 3E. At some time during the head/shaft connection process, a shaft 106 is engaged within the cylindrical interior chamber 208 of the connection assembly 200. In this illustrated example structure 200, the shaft 106 will be permanently engaged in the chamber 208, e.g., via an adhesive or cement bond. Other ways of engaging a shaft 106 with the connection assembly 200 are possible without departing from this invention, including, for example, mechanical connections (including releasable mechanical connections, such as threaded structures or the like); welding, brazing, soldering, or other fusing techniques; etc. Once connected to the connection assembly 200, the shaft 106 is ready for mounting to a golf club head 102. Alternatively, if desired, the shaft 106 may be connected to the connection member 200 later in the process, even as late as the final step in the connection process.

An example club head structure 102 now will be described in more detail, particularly in conjunction with FIGS. 3A and 3B (FIG. 3B provides an overhead view of the club head 102, without a shaft 106 engaged therewith, looking down the hosel opening). In this example structure, the club head 102 includes a hosel area 302 that provides access to a shaft-receiving chamber 304 defined in the club head 102. The shaft-receiving chamber 304 in this example structure extends completely through the club head body 102 and produces an opening 306 at the sole of the club head 102. This opening 306 allows access for insertion of a securing system 308 (e.g., a threaded bolt member) that helps secure the connection system 200 to the club head body 102, as will be described in more detail below. In this example structure, the shaft-receiving chamber 304 includes a mounting plate 310 with a hole 310 a defined therein, which provides a support surface for securing the connection system 200 within the club head body 102, as will be explained in more detail below. If desired, the mounting plate 310 may be integrally formed as part of the club head structure, and it may be located at any desired position along the shaft-receiving chamber 304, including right at or near the opening 306. Additionally or alternatively, if desired, a plug member may be provided close to opening 306 (optionally a removable plug member) or the sole member may include a countersunk region to allow the bolt member 308 to lie flush or substantially flush with the club head sole.

The upper opening for the shaft-receiving chamber 304 in this example structure has rotation-inhibiting structures 312. While a variety of rotation-inhibiting structures 312 may be used without departing from the invention, in this example structure, the rotation-inhibiting structure 312 constitutes an opening having a plurality of flat sides or edges 312 a that generally correspond to the size, shape, and location of the rotation-inhibiting structure 212 (and flat panels 212 a) of the connection member 200 (e.g., having a non-round opening, and in this illustrated example, a polygonal opening with flat sides or edges 312 a). As noted above, a variety of rotation-inhibiting structures 312 and/or 212 may be used without departing from this invention.

Connection of the connection assembly 200 (optionally with a shaft 106 already engaged with it) to the club head 102 will be described in more detail in conjunction with FIGS. 3A, 3C, 3D, and 3E. As shown, the cylindrical body 202 of the connection member 200 is inserted into the shaft-receiving chamber 304 of the club head body 102 in an appropriate manner such that the rotation-inhibiting structures 212 a of the connection member 200 engage the rotation-inhibiting structures 312 a of the hosel 302. At this location and in this arrangement, the second end 206 of the connection member 200 is seated against the mounting plate 310 and/or the expanded portion 214 of the connection member 200 first end 204 is seated against the top surface of the hosel 302 opening.

Once inserted, the connection assembly 200 may be engaged with the club head body by inserting the securing system 308 through the opening 306 in the sole of the club head and engaging the securing system 308 with the securing structure 210 provided with the connection member 200. If desired, the locations where the connection member 200 meet the club head 102 (e.g., at mounting plate 310 and/or the hosel opening) and/or where the securing system 308 meets the club head 102 (e.g., at the mounting plate 310) may include a flexible material (such as a washer, a gasket, an o-ring, an elastomeric washer or coating, etc.) to provide noise and/or vibration dampening, etc. This illustrated connection system is readily releasable, e.g., by twisting out the bolt member 308, to allow users to interchange different shafts 106 on a given golf club head 102 and/or to allow users to interchange different golf club heads 102 on a given shaft/connection member assembly. If desired, the bolt 308 and mounting plate opening 310 a may be structured so as to prevent the bolt 308 from completely falling out of the opening 306 when the bolt 308 is released from the connection system 200 (e.g., by providing an enlarged ring on the free end of bolt 308). The bolt may include a head having structures for engaging a screwdriver, an allen wrench, or another tool.

As will be explained in more detail below in conjunction with FIGS. 4A through 6B, adjustment of the rotational position of the connection system 200 (and its attached shaft 106) with respect to the golf club head 102 may be used in at least some examples of this invention to adjust various features of the overall golf club, such as loft angle, lie angle, inset distance, offset distance, to fade bias, to draw bias, etc. To enable users to easily identify the club head's “settings” (e.g., the club head body 102 position and/or orientation with respect to the shaft 106), any or all of the shaft 106, the connection member 200, and/or the club head 102 may include markings or indicators. FIGS. 2A and 3A shows an indicator 220 on the connection system 200 (e.g., on the expanded portion 214), and FIG. 3A shows plural indicators 320 on the hosel area 302 of the club head 102. By noting the relative positions of the various indicators, a club fitter or other user can readily determine and know the position of the shaft with respect to the club head body 102 and its ball striking face. If desired, the indicators (e.g., indicators 320) may be associated with and/or include specific quantitative information, such as a specifically identified loft angle, lie angle, inset distance, offset distance, etc.

Additional aspects of this invention relate to utilizing releasable golf club head/shaft connection assemblies to enable club fitters (or others) to adjust various positions and/or angles of the club head (and its ball striking face) with respect to the free (grip) end of the shaft (e.g., lie angle, loft angle, etc.). FIGS. 4A and 4B illustrate one example golf club head/shaft connection system 400 in which these angles can be controlled and adjusted. More specifically, FIGS. 4A and 4B illustrate a releasable golf club head/shaft connection assembly 200 similar to that described above in conjunction with FIGS. 1 through 3E (the same or similar reference numbers are used in FIGS. 4A and 4B as those used in FIGS. 1 through 3E to denote the same or similar parts). The shaft 402, however, in this example structure 400, is bent so as to include a first axial direction 404 extending coaxial with the interior chamber 208 of the connection member 200 and a second axial direction 406 extending along a major portion of the shaft 402. The axial direction change region 408 (optionally an abrupt bend or a continuous and/or smooth change) transitions the shaft axial direction from the first direction 404 to the second direction 406.

As evident from a comparison of FIGS. 4A and 4B, the angle and/or position of the free end of the shaft 402 (at the location of the grip, remote from the connection assembly 200) may be altered with respect to the club head 102 (and with respect to the ball striking face) by rotating the connection member 200 with respect to the club head (note the changed location of the position indicator 220 of the connection member 200 in FIGS. 4A and 4B). For ease in illustration, the club head structure is not shown in FIGS. 4A and 4B, but its location with respect to connection member 200 is readily evident from the previously described figures. This bent shaft feature, along with the releasable connection system 200 (e.g., via releasable seouring system features 210 and 308), allows club fitters (or others) to freely and easily adjust various angles and/or positions of the shaft 402 with respect to the club head 102 (e.g., variable lie, loft, and face angle combinations) while still using the same shaft 402 and head 102, which can help users more easily determine the optimum club head/shaft combination and arrangement to suit their needs.

The axial direction change region 408 may be located at any desired position along the shaft 402 without departing from this invention. In at least some example structures 400 according to this aspect of the invention, the axial direction change region 408 will be located in the lower half of the shaft 402 nearer to the club head 102 than to the grip end. In some more specific examples, the axial direction change region 408 will be located in the lower quarter of the shaft 402 nearest to the club head 102, and even in the lower 10% or even 5% of the shaft 402 nearest to the club head 102. In some example structures 400 according to the invention, the bend or other axial direction change region 408 may be located as close to the connection member 200 or other portion of the club head as possible.

Also, any desired axial direction change θ (or bend) angle may be used without departing from this invention, e.g., at least 0.25 degrees, at least 0.5 degrees, at least 1 degree, at least 2 degrees, at least 4 degrees, or even at least 8 degrees. In some example structures, this bend or other axial direction change will be between 0.25 and 25 degrees, between 0.5 and 15 degrees, between 1 and 10 degrees, or even between 1 and 5 degrees.

Aspects of this invention are not limited to golf club shafts having a single axial direction change region. Rather, as illustrated by the structure 500 shown in FIG. 5A, the shaft 502 may have multiple axial direction change regions (e.g., regions 504 and 506 in FIG. 5A (in FIG. 5A, the same or similar reference numbers are used as those used in FIGS. 1 through 4B to denote the same or similar parts)). This double bend feature allows further fine tuning or control of the position and/or angle of the free end of the shaft 502 (at the grip) with respect to the club head 102 and its ball striking face (e.g., to adjust positions to provide a range of inset, outset, onset, and offset positions and/or optionally to adjust lie, loft, and/or face angle features). For simplicity in illustration, the club head 102 is not shown in FIG. 5A.

FIG. 5B illustrates another example structure 520 including a releasable golf club head/shaft connection assembly (e.g., like assembly 200) and a shaft 522 having two (or more) axial direction change regions 504 and 506 like those illustrated in FIG. 5A. In this example structure 520, however, the shaft 522 has more abrupt direction changes as compared to the structure 500 and shaft 502 of FIG. 5A. This shaft structure 522 also allows control of the position and/or angle of the free end of the shaft 522 (at the grip) with respect to the club head 102 and its ball striking face (e.g., to adjust positions to provide a range of inset, outset, onset, and offset positions and/or optionally to adjust lie, loft, and/or face angle features).

The axial direction change regions 504 and 506 in the various structures (e.g., structures 500 and 520) may be located at any desired positions along the shafts 502 and/or 522 and/or at any desired relative spacing with respect to one another without departing from this invention. In at least some example structures 500 and/or 520 according to this invention, at least one of the axial direction change regions 504 and 506 (and optionally both) will be located in the lower half of the shaft 502 and/or 522 nearer to the club head 102 than to the grip end. In some more specific examples, one or both of the axial direction change regions 504 and 506 will be located in the lower quarter of the shaft 502 and/or 522 nearest to the club head 102, and even in the lower 10% or 5% of the shaft 502 and/or 522 nearest to the club head 102. The axial direction change regions 504 and 506 may be separated from one another by at least ½ inch, at least 1 inch, at least 2 inches, or even at least 4 inches or more without departing from this invention.

Also, any desired axial direction change (or bend) angles may be used for each of the two (or more) direction changes without departing from this invention, e.g., at least 0.25 degrees, at least 0.5 degrees, at least 1 degree, at least 2 degrees, at least 4 degrees, or even at least 8 degrees. In some example structures, like those shown in FIG. 5A, these bends or other axial direction changes will be between 0.25 and 25 degrees, between 0.5 and 15 degrees, between 1 and 10 degrees, or even between 1 and 5 degrees. In other example structures, like those shown in FIG. 5B, these bends or other axial direction changes will be between 25 and 145 degrees, between 30 and 120 degrees, between 45 and 100 degrees, or even between 60 and 90 degrees. If desired, one bend may be relatively slight (e.g., as shown in FIG. 5A) while another is more abrupt (e.g., as shown in FIG. 5B). The bends or axial direction changes 502 and 504 may be arranged so that the free ends of the shaft (and the shaft sections 524 and 526 including the free ends) lie on the same plane or on different planes. Also, if desired, more than two bends or axial direction change regions may be provided in a club head shaft structure without departing from this invention.

Utilizing a shaft including one or more axial direction change regions is not the only manner in which the position and/or angle of the free (grip) end of a shaft may be altered with respect to a golf club head and/or its ball striking face. FIGS. 6A and 6B illustrate another example arrangement. In this example arrangement, the club head/shaft connection member 600 includes an “off-axis” or angled bore hole or interior chamber 608 in which the shaft 106 (optionally a straight shaft) is received. More specifically, in this illustrated example, the outer cylindrical surface 618 of the connection member 600 extends in a first axial direction 626, and the interior cylindrical surface 628 of the bore hole 608 extends in a second axial direction 630 that differs from the first axial direction 626. In this manner, while the shaft connection member 600 exterior maintains a constant axial direction corresponding to that of the interior of the club head hosel and its opening, the shaft 106 extends away from the club head 102 at a different and adjustable angle with respect to the club head 102 and its ball striking face (the shaft position and/or angle may be adjusted, for example, by rotating the shaft connection member 600 with respect to the club head hosel). This may be seen, for example, by a comparison of the angles of FIGS. 6A and 6B.

While any desired angle may be maintained between the first axial direction 626 and the second axial direction 630, in accordance with some examples of this invention, this angle will be between 0.25 degrees and 10 degrees, and in some examples between 0.5 degrees and 8 degrees, between 0.75 degrees and 6 degrees, or even between 1 degree and 4 degrees.

As another example, if desired, the axial directions 626 and 630 may be parallel to one another but offset such that these directions are not coaxial. In this manner, various characteristics of the club may be changed by rotating the connection system 200 with respect to the club head (such as inset or outset dimensions, etc.).

Many variations in the overall structure of the shaft, club head, and club head/shaft connection assembly are possible without departing from this invention. For example, if desired, the connection system may be used to connect shafts to other elements of a golf club (or other) structure, such as connecting a golf club shaft to a grip element. Similar structures also may be used to connect shafts to other pieces of athletic equipment or other equipment, if desired (not limited to golf clubs). The various steps of the described assembly processes also may be altered, changed in order, combined, and/or omitted without departing from the invention.

Additionally, the releasable connection assemblies may be used in any desired manner without departing from the invention. The clubs with such connection assemblies may be designed for use by the golfer in play (and optionally, if desired, the golfer may freely change shafts, heads, and/or their positioning with respect to one another). As another example, if desired, clubs including releasable connections in accordance with the invention may be used as club fitting tools and when the desired combination of head, shaft, and positioning have been determined for a specific golfer, a club builder may use the determined information to then produce a final desired golf club product using conventional (and permanent) mounting techniques (e.g., cements or adhesives). Other variations in the club/shaft connection assembly parts and processes are possible without departing from this invention.

CONCLUSION

While the invention has been described in detail in terms of specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and methods. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. 

1. A golf club head/shaft connection assembly, comprising: a cylindrical structure having a first end and a second end opposite the first end, wherein the first end includes a first opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure nearer to the first end than the second end includes a rotation-inhibiting structure, and wherein the second end includes a securing structure; and a securing system for releasably engaging the securing structure.
 2. A golf club head/shaft connection assembly according to claim 1, wherein the securing structure includes a threaded hole defined in the second end of the cylindrical structure and the securing system includes a threaded bolt element that engages the threaded hole.
 3. A golf club head/shaft connection assembly according to claim 1, wherein the rotation-inhibiting structure includes plural flat sides that extend in an axial direction of the cylindrical structure.
 4. A golf club head/shaft connection assembly according to claim 1, wherein a portion of the exterior surface in a longitudinal direction of the cylinder structure has a non-round cross section to thereby provide the rotation-inhibiting structure.
 5. A golf club head/shaft connection assembly according to claim 1, wherein a portion of the exterior surface in a longitudinal direction of the cylinder structure has a polygonal shaped cross section to thereby provide the rotation-inhibiting structure.
 6. A golf club head/shaft connection assembly according to claim 1, wherein the rotation-inhibiting structure extends less than 35% of an overall axial length of the cylindrical structure.
 7. A golf club head/shaft connection assembly according to claim 1, wherein the exterior surface of the cylindrical structure and the cylindrical interior chamber are coaxial.
 8. A golf club head/shaft connection assembly according to claim 1, wherein the exterior surface of the cylindrical structure and the cylindrical interior chamber are not coaxial.
 9. A golf club head/shaft connection assembly according to claim 1, wherein the exterior surface of the cylindrical structure at the first end includes a tapered portion that tapers from a narrower width at the first end to a wider width proximate to a location where the rotation-inhibiting structure begins on the exterior surface, and wherein the exterior surface of the cylindrical structure abruptly changes width in an axial direction thereof such that the exterior surface abruptly changes width with from the wider width to a narrower width corresponding to the rotation-inhibiting structure.
 10. A golf club head/shaft connection assembly according to claim 1, wherein the exterior surface of the cylindrical structure at the first end includes a rotational position indicator located between the first end and a location where the rotation-inhibiting structure begins.
 11. A golf club, comprising: a golf club head having a shaft-receiving chamber, wherein a first end of the shaft-receiving chamber includes a first rotation-inhibiting structure and a second end of the shaft-receiving chamber includes a first opening for receiving a securing member; a shaft connection member extending into the shaft-receiving chamber of the golf club head, the shaft connection member including a cylindrical structure having a first end and a second end opposite the first end, wherein the first end of the shaft connection member includes a second opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure nearer to its first end than its second end includes a second rotation-inhibiting structure that engages the first rotation-inhibiting structure, and wherein the second end includes a securing structure; a shaft engaged in the cylindrical interior chamber of the shaft connection member; and a securing member extending into the second end of the shaft-receiving chamber of the golf club head and releasably engaging the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with the golf club head.
 12. A golf club according to claim 11, wherein the securing structure of the shaft connection member includes a threaded hole defined in the second end of the cylindrical structure and the securing member includes a threaded bolt element that engages the threaded hole, and wherein the threaded bolt element releasably engages the golf club head to hold the shaft connection member in place with respect to the golf club head.
 13. A golf club according to claim 11, wherein at least a portion of the first end of the shaft-receiving chamber includes an opening having a non-round cross section to thereby provide the first rotation-inhibiting structure, and wherein a portion of the exterior surface in a longitudinal direction of the cylinder structure of the shaft connection member has a mating and correspondingly shaped non-round cross section to thereby provide the second rotation-inhibiting structure.
 14. A golf club according to claim 11, wherein at least a portion of the first end of the shaft-receiving chamber includes an opening having a polygonal shaped cross section to thereby provide the first rotation-inhibiting structure, and wherein a portion of the exterior surface in a longitudinal direction of the cylinder structure of the shaft connection member has a mating and correspondingly shaped polygonal shaped cross section to thereby provide the second rotation-inhibiting structure.
 15. A golf club according to claim 11, wherein a portion of the first end shaft connection member remains outside of the shaft-receiving chamber of the golf club head, and wherein the second rotation-inhibiting structure extends into the shaft receiving chamber and engages the first rotation-inhibiting structure.
 16. A golf club according to claim 11, wherein the exterior surface of the cylindrical structure proximate the first end of the shaft connection member includes a first rotational position indicator, wherein the first rotational position indicator is located on the exterior surface between the first end of the shaft connection member and a location where the second rotation-inhibiting structure begins, and wherein the golf club head includes a second rotational position indicator located proximate to the shaft-receiving chamber.
 17. A golf club according to claim 11, wherein the first opening of the shaft receiving chamber is located at a sole surface of the golf club head.
 18. A golf club according to claim 11, wherein the shaft-receiving chamber includes an interior surface through which the first opening of the shaft-receiving chamber is defined.
 19. A golf club according to claim 1 1, wherein the shaft includes a shaft axial direction change region.
 20. A golf club according to claim 11, wherein the shaft includes at least two shaft axial direction change regions.
 21. A method of producing a golf club head/shaft connection assembly, comprising: producing a shaft connection member as a cylindrical structure having a first end and a second end opposite the first end; producing an open cylindrical interior chamber for receiving a golf club shaft at the first end of the shaft connection member; forming a rotation-inhibiting structure as part of an exterior surface of the cylindrical structure nearer to the first end than the second end; forming a securing structure at the second end of the shaft connection member; and providing a securing member for engaging the securing structure.
 22. A method of assembling a golf club, comprising: providing a golf club head having a shaft-receiving chamber, wherein a first end of the shaft-receiving chamber includes a first rotation-inhibiting structure and a second end of the shaft-receiving chamber includes a first opening for receiving a securing member; engaging a shaft with a shaft connection member, wherein the shaft connection member includes a cylindrical structure having a first end and a second end opposite the first end, wherein the first end of the shaft connection member includes a second opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure nearer to its first end than its second end includes a second rotation-inhibiting structure that engages the first rotation-inhibiting structure, and wherein the second end of the shaft connection member includes a securing structure; placing at least a portion of the shaft connection member into the shaft-receiving chamber of the golf club head such that the first rotation-inhibiting structure engages the second rotation-inhibiting structure to inhibit rotation of the shaft connection member with respect to the golf club head; placing a securing member into the second end of the shaft-receiving chamber; and releasably engaging the securing member with the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with the golf club head.
 23. A method according to claim 22, further comprising: releasing the shaft connection member with respect to the golf club head; engaging a second shaft with a second shaft connection member, wherein the second shaft connection member includes a cylindrical structure having a first end and a second end opposite the first end, wherein the first end of the second shaft connection member includes a second opening that defines a cylindrical interior chamber for receiving a golf club shaft, wherein an exterior surface of the cylindrical structure of the second shaft connection member nearer to its first end than its second end includes a third rotation-inhibiting structure, and wherein the second end of the second shaft connection member includes a second securing structure; placing at least a portion of the second shaft connection member into the shaft-receiving chamber of the golf club head such that the first rotation-inhibiting structure engages the third rotation-inhibiting structure to inhibit rotation of the second shaft connection member with respect to the golf club head; placing the securing member into the second end of the shaft-receiving chamber; and releasably engaging the securing member with the second securing structure of the second shaft connection member to thereby releasably engage the second shaft connection member with the golf club head.
 24. A method according to claim 22, further comprising: releasing the shaft connection member with respect to the golf club head; and releasably engaging an assembly including a second shaft with the shaft-receiving chamber of the golf club head.
 25. A method according to claim 22, further comprising: disengaging the shaft connection member from the golf club head; changing a position of the shaft connection member with respect to the golf club head to thereby alter a position of a free end of the shaft with respect to a ball striking face of the club head; and releasably engaging the securing member with the securing structure of the shaft connection member to thereby releasably engage the shaft connection member with respect to the golf club head at the changed position. 